Investigators gather evidence after an overnight police pursuit ended in a shooting and crash just east of Yerba Buena Island on the lower deck of the Bay Bridge in San Francisco, Calif. on Thursday, July 5, 2012. The Highway Patrol closed off four-lanes of eastbound traffic for several hours snarling traffic heading for the East Bay.

Photo: Paul Chinn, The Chronicle

Investigators gather evidence after an overnight police pursuit...

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Authorities remain on the scene on the lower deck of the Bay Bridge after an overnight police pursuit ended in a shooting and crash just east of Yerba Buena Island in San Francisco, Calif. on Thursday, July 5, 2012. Investigators closed off four-lanes of eastbound traffic for several hours snarling traffic heading for the East Bay.

Photo: Paul Chinn, The Chronicle

Authorities remain on the scene on the lower deck of the Bay Bridge...

Image 3 of 6

Investigators collect evidence after an overnight police pursuit ended in a shooting and crash just east of Yerba Buena Island on the lower deck of the Bay Bridge in San Francisco, Calif. on Thursday, July 5, 2012. The Highway Patrol closed off four-lanes of eastbound traffic for several hours snarling traffic heading for the East Bay.

Photo: Paul Chinn, The Chronicle

Investigators collect evidence after an overnight police pursuit...

Image 4 of 6

Eastbound traffic is reduced to a crawl after an overnight police pursuit ended in a shooting and crash just east of Yerba Buena Island on the lower deck of the Bay Bridge in San Francisco, Calif. on Thursday, July 5, 2012. The Highway Patrol closed off four-lanes of traffic for several hours during the investigation.

Photo: Paul Chinn, The Chronicle

Eastbound traffic is reduced to a crawl after an overnight police...

Image 5 of 6

Eastbound traffic is reduced to a crawl after an overnight police pursuit ended in a shooting and crash just east of Yerba Buena Island on the lower deck of the Bay Bridge in San Francisco, Calif. on Thursday, July 5, 2012. The Highway Patrol closed off four-lanes of traffic for several hours during the investigation.

Photo: Paul Chinn, The Chronicle

Eastbound traffic is reduced to a crawl after an overnight police...

Image 6 of 6

Eastbound traffic is reduced to a crawl after an overnight police pursuit ended in a shooting and crash just east of Yerba Buena Island on the lower deck of the Bay Bridge in San Francisco, Calif. on Thursday, July 5, 2012. The Highway Patrol closed off four-lanes of traffic for several hours during the investigation.

The driver involved in a predawn Bay Bridge car chase and shooting that forced the closure of most eastbound lanes Thursday morning was on parole for human trafficking, the California Highway Patrol said.

Parolee Antonio Roberson, 29, of Oakland, was arrested on suspicion of felony drunken driving and weapons charges, including being a felon in possession of a gun.

Officer Michael Ferguson, a CHP spokesman, said Roberson was allegedly drunk when he sped past CHP officers on the lower deck in a Cadillac El Dorado at 1:34 a.m.

Before officers could catch up to the car, it slammed into the guardrail near the S-curve just east of Yerba Buena Island, Ferguson said. The car managed to go another 700 feet before coming to a halt.

As officers approached, shots rang out, Ferguson said. Although authorities are investigating the incident as an officer-involved shooting and Roberson faces weapons charges, Ferguson would not say who fired the first shots.

No one was hit, but the driver and his passenger - Olivia Benehy, 26, of Australia - were treated for injuries related to the crash, Ferguson said. Benehy was not arrested and has been released from the hospital.

Roberson was medically cleared as of 4 p.m., and was scheduled to be booked into County Jail, Ferguson said. No details were available about his earlier conviction.

Officers closed most eastbound lanes on the bridge until about 10 a.m., causing hours-long delays extending back to San Francisco.